The present invention generally relates to air conditioning systems and, more particularly, to an electrically driven air conditioning system for an aircraft that does not rely on engine bleed air.
Many air conditioning systems employed in modern commercial aircraft utilize the air-to-air thermodynamic cycle to provide cooling and/or heating air to the various compartments on the aircraft, such as the passenger cabin, cargo holds, and the like. Air from the compressor stages of the main jet propulsion engines, also known as xe2x80x9cbleed air,xe2x80x9d is generally output at high temperature and pressure (i.e. 610xc2x0 F. and 60 psi). Conventionally, this bleed air is then conditioned through conditioning packs before passing into the pressurized fuselage for cabin temperature control, ventilation, and pressurization. This conditioned air within the fuselage is then discharged to the outside ambient air through various overboard valves, overflow valves, and cabin leaks.
This known method of conditioning air for use with the various aircraft systems is inefficient. That is, during a typical steady state cruise operation, more energy than is necessary for the primary requirements of the conditioning system (e.g. cabin temperature control, ventilation, and pressurization) is added into the conditioning system at the engines in the form of additional fuel. Much of this excess energy is wasted in the form of heat and pressure drop through ductwork, valves, and various other components of the conditioning system. Moreover, extracting work from the engines in the form of bleed air is inefficient relative to other extraction methods. Consequently, the use of bleed air from the engines reduces the efficiency of the engines and, thus, increases the fuel consumption and load on the engines. By eliminating or at least minimizing the use of bleed air in the various aircraft systems, it is believed that more efficient jet engines may be developed. Moreover, it is believed that alternative air conditioning systems may lead to a reduction in aircraft weight, assembly complexity, and fuel consumption.
Accordingly, there exists a need in the relevant art to provide an air conditioning system for an aircraft that does not rely on jet engine bleed air for operation. Furthermore, there exists a need in the relevant art to provide an air conditioning system for an aircraft that is capable of reducing the aircraft weight, assembly complexity, and fuel consumption. Still further, there exists a need in the relevant art to provide an air conditioning system for an aircraft driven by electrical energy. Moreover, there exists a need in the relevant art to provide an air conditioning system for an aircraft that overcomes the disadvantages of the prior art.
An all electric air conditioning system for an aircraft, wherein the aircraft defines an interior volume having conditioned air at a first pressure, is provided having an advantageous construction. A compressor is provided and is operable to compress supply air to a second pressure. The compressor being operated in response to an electrical drive motor. A passage fluidly couples the compressor and the interior volume of the aircraft. A heat-dissipating device, such as a heat exchanger, is positioned in the passage to extract heat energy from the supply air. This arrangement permits conditioning of air within the aircraft without using bleed air from the engines. The use of bleed air results in a significant amount of fuel burn. An optional conditioned air recovery system may be coupled to the interior volume of the fuselage to direct at least a portion of the conditioned air from the interior volume back for further conditioning and use.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.